8. Agnosia, Neglect & Dyslexia Flashcards
What do damages to the dorsal and ventral pathway causes?
Damage to dorsal pathway leads to impaired goal direction “action”;
Damage to the ventral pathway leads to agnosia, therefore person can see an object but cannot perceive/ understand what the object is → Visual agnosia
What is Visual Object agnosia?
Visual object agnosia is when a person can see but cannot perceive or understand what the object is. This is due to lesion to the ventral pathway, usually caused by damage to the fusiform, lingual and adjacent part of the posterior cingulate gyro. There are two types: apperception agnosia and associative agnosia.
What is Optic Ataxia?
Optic ataxia is when a person cannot perceive spatial orientations. This is due to lesion in the dorsal stream, such as lesion in the right posterior parietal cortex. When given a card to put through slots by matching orientations, the person will not be able to do this properly.
What is Visual Neglect? What happens during a line bisection task and a cancellation task?
Visual neglect is when a person ignores one side of the visual field, usually caused by lesion in the posterior parietal region. Such that when they are drawing, they will only draw on one side. During a line bisecton task, px with he is partial neglect will typically place the mark towards the ipsilateal end of the line. DUring a cancellation task, px will omit cancelling its E in one half of the field.
The posterior parietal cortex is part of the .... It plays a central role in ... in order to enable .... This part of the brain also helps .... This part gates inputs into the .... There are evidence that it is linked to ..., thus affects reading abilities.
The posterior parietal cortex is part of the ` dorsal stream. It plays a central role in directing attention to spatial locations in order to enable action. This part of the brain also helps binding different attributes of an object together. This part gates inputs into the ventral stream. There are evidence that it is linked to dyslexia`, thus affects reading abilities.
Phonological processing refers to the ability to ... e.g. identify words that ..., alliterations, count the... etc. Studies suggest that ... predict later reading failure. ... children have difficulties in ... and ....
Phonological processing refers to the ability to perceive and manipulate elementary sounds of a language e.g. identify words that rhyme, alliterations, count the syllables in a word etc. Studies suggest that pre-reading phonological skills predict later reading failure. Dyslexic children have difficulties in discriminating syllables and rapid acoustic stimuli.
Surface dyslexia (...) is when a person’s ... affects ..., therefore they have trouble with recognising ..., especially if the words ... such as yacht, enough;
Phonological dyslexia (...), which makes up 63% of all dyslexias. This is the difficulty in reading due to ... affecting the auditory word recognition system. There is also a mixed type, ..., which makes up ...%. Studies have found that ... improves phonemic awareness.
Surface dyslexia (Dyseidesia) is when a person’s visual processing affects visual word recognition, therefore they have trouble with recognising whole words, especially if the words don't sound like the way they are spelt such as yacht, enough; Phonological dyslexia (Dysphonesia), which makes up 63% of all dyslexias. This is the difficulty in reading due to phonological impairment affecting the auditory word recognition system. There is also a mixed type, Dysphoneidesia, which makes up 28%. Studies have found that orthographic training = reading improves phonemic awareness.
In the brain, the ... and the ... are the two main pathways connecting the brain regions involved in reading. Both have shown correlation of their ... with .... ... makes profound changes to the brain tracts.
In the brain, the left superior longitudinal fasciculus and the left arcuate fasciculus are the two main pathways connecting the brain regions involved in reading. Both have shown correlation of their size with reading scores. Language exposure makes profound changes to the brain tracts.
... deficits have been associated with dyslexia. Low contrast stimuli elicit poorer ... in dyslexic individuals compared to controls. MRI also shows that their ... are smaller in volume. There is also impaired ... both psychophysically and in fMRI. Some studies have found specific deficits in ... in the ... found in dyslexia. Logically, one would expect the ... pathway to be more important due to reading needing the ability to .... However, the ... seems to have a ... that controls what goes into the ....
Magnocellular deficits have been associated with dyslexia. Low contrast stimuli elicit poorer visual evoked potentials in dyslexic individuals compared to controls. MRI also shows that their LGN Magno layers are smaller in volume. There is also impaired visual/ illusory motion sensitivity both psychophysically and in fMRI. Some studies have found specific deficits in temporal processing in the magnocellular-dorsal stream pathway found in dyslexia. Logically, one would expect the parvocellular pathway to be more important due to reading needing the ability to follow fine print and recognise individual letters through the ventral stream of object recognition. However, the dorsal stream seems to have a gating system that controls what goes into the ventral system.
How are the attentional engagement and disengagement with dyslexic children?
Both attentional engagement and disengagement are poorer in dyslexic children. They have poorer attention magnitude and therefore overall longer reaction time.
Learning to read is probably a process of ... along the visual scene. This will not be easy, because the .... Since the attentional spotlight depends upon the ..., any impairment of the ... can lead to reading problems.
Learning to read is probably a process of training the attentional spotlight to move sequentially along the visual scene. This will not be easy, because the visual search mechanisms are random and do not have memory. Since the attentional spotlight depends upon the integrity of Magno pathway and the dorsal stream, any impairment of the Magno pathway or the parietal cortex can lead to reading problems.
How does poor attention magnitude affect dyslexic individuals and normal readers?
Both correlate with slower reading
What remedial measure has been fond to improve reading in children?
12 hours of action video game playing, not involving any direct phonological or orthographic training, was found to drastically improve the reading abilities of children with dyslexia,
